Refrigerator vehicle



Nov. 22, 1938.

D. c. ARTHURS x`:r Al.

REFRIGERATOR VEHICLE 193e 2 sheets-sheet 2 Filed Nov. 21

Ps. 7.x

I Patented Nev. 22l, 1938 2,137,766

UNITED STATES PATENT OFFICE v REFRIGERATOR VEHICLE David C. Arthurs and Josse A. Guyer, Mount Vernon, Ill., assignors to Mt. Vernon Car Mig. Co., Mount Vernon, Ill., a corporation of Illinois Application November 21, 1936, Serial No. 111,978

l 1 Claim. (Cl. (i2-91.5)

This invention relates to refrigerator vehicles, point of most all materials transported in suchY and with regard to certain more specific features, equipment. Although many systems have been to cars and trucks of a type adapted to be used proposed to control the rate of refrigeration and on railways, highways, and the like. maintain the desired temperature in the body of Among the several objects of the invention a car ortruck, most of the proposed systems are may be'y noted the provision of means for con-- too expensive to install, require frequent repairs, verting the water-ice compartments now used in and require moving partssuch as fans and refrigerator vehicles into an effective dry-iceA pumps. compartment (carbon-dioxide-ice); the provision The use of the ordinary secondary refrigeratof apparatus o`f the class described which shall ing materials is objectionable because of their l make maximum use of the facilities now availoriginal expense and possible injurious effect able in connection with water-ice cooling comupon the material being transported. Such mapartments but which will avoid their disadvanterlals increase the weight of the non-pay load, tages; the provision -of apparatus of the class arid when they leak out of the system damage the described which is automatic in maintaining pay load. Materials such as alcohol are highly desirable temperatures in thecar, without effectinflammable and are a lire hazard. ing excessively cooled areas therein; and the prol. z The system described herein is designed to vision of improved apparatus of the class de- `overcome the above-mentloned difficulties of the scribed in cars not previously provided with any previous systems, and can be installed in the means of refrigeration. Otherobjects will be in present refrigerated cars or trucks with a minipart obvious and in part pointed out hereinafter. mum of expense both for installation, operation,

The invention accordingly comprises the eleand up-keep. One of the most important feaments and combinations of elements, features of tures of this system is that it can be installed in construction, and arrangements of parts which refrigerator cars originally equipped to use waterwill be exemplified in the structures hereinafter ice. Consequently, `the car can be refrigerated described, and the scope of the application of with either dry-ice or water-ice conditions which will be indicated in the following claim. require. It eliminates the deleterious secondary In the accompanying drawings, in which are refrigerants and all moving parts such as fans or illustrated several of various possible embodiments pumps, requiring power for. operation. -The iniof the invention, y tial cost of installation is low, andthere is prac- 30 Fig. 1 is a longitudinal section of an end of tically nonp-keep cost. The invention also prea railway refrigerator car4 (for example), showvents the relatively cold dry-ice refrigerant from ing theA invention; v locally over-cooling the region of the car adja- Fig. 2 is a vertical section taken on line 2-j-2 cent the dry-ice compartment. of Fig. 1; Referring now more particularly to Fig. 1, there 35 Fig. 3 is an enlarged detail showing certain is illustrated by way of example the end of a raildamper operating means; road refrigerator car having an insulated top l, `Fig. 4 is a view similar to Fig. 1 showing a an insulated bottom 3, insulated sidewalls 5, and modification; and, insulated end walls l. Heretofore cars of this Fig. 5 is a vertical section taken on line 5 5 type have been provided at their ends with water- 40 of Fig. 4. ice compartments or bunkersv which have been Similar reference characters indicate correseparated from the remainder of the car merely spending parts throughout the several views of by a'suitable separating wall. inasmuch as this the drawings. compartment was filled with water-ice through Many railway refrigerator cars and highway an opening such as shown at Il, and said watermotor cars or trucks are now equipped with ice could never attain a temperature while meltwater-ice compartments for refrigeration en`. ing less than 32 F., there was never experienced route. It has been proposed to use, instead of any trouble oi' local freezing adjacent to said the water-ice refrigerant, the now available separating wall. However, when compartments and socalled dry-ice, or frozen carbon-dioxide such as 9 are loaded with dry-ice, the tempera- 50 (CO2) y tures adjacent the separating wall are so low as The most serious objection to using dry-ice to locally freeze products adjacent the wall Withas a refrigerant, without 4some means of conout eil'iciently cooling the remaining products in trolling the temperature, is its low temperature the car. i i (minus 109f FJ, which is below the freezing `The present invention comprises the separat- 55 mw che duct l1 lean return upper ducts zn and 2| located at the sides of the'car and near the ceiling. These ducts are provided with return openings 23 and control valves or dampers 25. By means of parallel linkages 21 the valves 25 are coupled with a valve 28 at the lower end of the duct I1. The linkage, as shown in the drawings,

is such that the valves 2B and '2l operate in unison to open and close.

Leading from the lower end of the duct I1 are two delivery ducts 3l in opposite corners of the bottom of the car, and these have outlets 33, through which cold air emanates into the load compartment 5.

The valves or dampers 25 and 2l are provided with operating meansby coupling a stem 31 to the lever 35 of one of the valves 25 (Fig. 3) The stem 31 is attached to one closed end of a nexible. extensible, metallic bellows 39. A return spring 4I normally presses the en d 31 in the direction to compress the bellows 3B. yThe interior of the bellows 35 communicates at its other end. by means of a iiexible tube I3, with the inside of a fluid chamber 45. The chamber 4B has therein a volatile fluid such as etheror the like, which has auseful vapor pressure at the temperatures over which refrigerating control is to be effected. The vessel 45 is placed at a suitable point within the car for responding to temperature changes.

The vessel I5 may be referred to as the dry-ice chest and it is gas-tight when closed, with the exception of a -lower small opening 41 through which the gas formed by the sublimation ofthe dry-ice sinks to the outside atmosphere. It is to be understood that the chest Il is made oi' metal and is not insulated so that it quickly cools the air inthe chamber l. The air in the chamber Q has a tendency to circulate as indicated. It circulates down on the side of the ice chest Il and up adjacent to the wall Il.

. It will be seen that by venting the ice chest Ilv directly to the outside atmosphere, that the refrigerant compartment j can be and is maintained entirely closed without any inside pressure. Furthermore air circulation in the refrigerator compartment I will be nnhampered therein by any outside connection.

,Operation is as follows:

The car is loaded with a pay load in the compartment I, and vessel. Il is filled with frozen c bon-dioxide. When the load is placed in the ca its temperature being high, heat is transferr to the volatile iiuid in the member 4l, which expands and elongates the bellows` 3l against the action of spring 4I. This causes the lever I! to be thrown to a position wherein the valves II and 29A are throwntoward open position.

' This allows circulation of air down through the duct I1 (by reason of increase in density as the air cols) out from the ducts 3|, up through the tothe load which it carries.

29. It will be seen that there is a counter-now between the rising air on the one side oi. the metal wall I9 and the descending air on the other side in duct I1, this being conducive to a high eiiiciency of heat transfer. Whenever the load tends vto warm up, the cycle tends to repeat itself.

.An advantage of having the ice chest i5 located at a point spaced from the wall i9 is that the ait` within the compartment 9 forms an intermediate, safe, inexpensive secondary circulating medium for absorbing heat generally over thewhole Wall i9, rather than permitting the exceedingly cold carbon-dioxide to abstract heat from this wall at a high rate over a local region which would tend to excessively cool the air at one point, andv to increase the condensation and dehumidiilcation of the contents of the pay load. Such humidication is undesirable, and it is the iimction of the circulating air in the compartment l to reduce the temperature head across the wall Il, and thus hold the air in the duct I1 at as high a temperature as possible consistent with the desired cooling effect. This reduces the condensation and maintains the pay load at a higher humidiflcation. Inasmuch as the entire condensation cannot be eliminated, a suitable drain Il is provided in the bottom of the duct I1.

'I'he reason for the valve 2l being at the junction between the ducts 2li and 2i with the duct I1 on the one hand, and the valve 2l at the base oi the duct onv the other hand, is to effectively block off any local circulation up and down through. the duct I1 from its bottom when the thermostatic apparatus calls for no more cooling effect.

It is to be understood that the responsive member 45 may be positioned at any suitable point within the car, and it maybe movable. Also, several controls may be used and connected toqinfi dependent duct systems, if desired. It is also to be understood that the control characteristics of the thermostatic system may be varied byvad-I ,iusme t of a suitable control screw II which varies thev reaction characteristics of spring I i. Thus the temperature of the car may be adapted In this connection.' one of the advantages of the use of dry-ice is that meat products and the/like may actually be frozen in the car; whereas this could not be done with plain water-ice. At the same time, the freezing temperatures need not be endured .loads which are not adapted to them. j l

In Figs. 4 and 5 is shown another form oi' the invention in which like numerals designate like parts. Many refrigerator cars are provided with .battens forming a false, reticulated bottom so that' theproducts in the car do not restdirectly upon themain bottom of the car. 'Ihis is to obtain circulation thereunder. Advantage is taken oi' this construction by' applying over battens OI a false bottom having openings Il therein, thus providing the equivalent of the lower side ducts 3| used in the form of the invention shown in Flgs. 1 and 2.

Thesp'aces between the battens ll and under the bottom are in' direct communication with the lower end o i' the duct I1. This form of the lnvention also results in excellent distribution of the cool airbeneath the load.

Another modification shown in Figs'. 4 and 5l is the substitution for two of the upper valves 2l, of a single valve 2l which reaches across the entire upper end of the passage I1. lIn this there is substitu for the passages 1l and 2| of Figs. 1 and 2 a single nat passage 2l extending across the entire roof of the car having openings 30 through which openings 30 takes place circulation from the load.fThe stem 3l from the member 39 passes loosely through an opening in the bottom of passage 28. This is proper because such an opening performs a circulating function similar to the opening 30. Duplicate control links 2'I are indicated as connecting the single valve 26 and valve 29 in Figs. 4 and 5, but it will be understood that in this case one of these (for example, the left-hand'link 21 in Fig. 5) may be eliminated. However, duplicate links serve to facilitate steady action.

It will be apparent to anyone skilled in this art that the single valve 26 in Figs. 4 and 5 serves a function similar to the va1ves25 in Figs. 1 and 2. The valve 26 in Figs. 4 and 5 primarily increases the cross section of the air circuit at the region where said circuit is controlled.

A feature of the invention is the provision `of the valve means 25 or 26 at the upper end of the 4 duct I1 and of the valve means 29 at the lower end thereof. This valve means, when shut, results in blocking off substantially all of the cooling areal of the wall I9 from communicating with the load compartment 4. It is this cutting oi of communication which prevents local circulation through any communicating means, whereby uncontrolled and undesired cooling would proceed. v The small area of the wal1r|9 below the valve 29 is of little consequence in obtaining the result here referred to. If desirable, even this small area may be included between the valves 25 and 29 by placing the valve 29 directly at the outlet ducts- 22. The reason they are, not thus shown is that it is more convenient to have the valve 29 in the location shown in the drawings.

Further advantages of the invention are that, inasmuch as control of the otherwise excessively low temperature produced by the dry-ice is provided for, use can be.-made of the desirable dry- 'ice form of refrigeration which has a theoretical duct l1 run from thetop of the car (and top o! the refrigerating cOmpartment) to the bottom of the -car (and bottom of the refrigerating compartment). By this means the rate of gravityinduced circulation of air is made a maximum. This means that the cold iluid 'in the refrigerating compartment and the warmer fluid in the duct I1 are not only in contact for a maximum period but also have the added effect of prolongingY the period of heat exchange and thus improving the convection currents, both within the refrigerating compartment and throughout thev ducts connected with the load compartment.

In view of theA above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description lor shown in the accompanying drawings shall be interpreted as illustrative and not in a hunting sense.

We claim:

A refrigerator vehicle comprising a load compartment, a refrigerating compartment separated from the load compartment -and containing secondary air, a duct extending from the top of the load compartment and entering into the top of the refrigerating compartment, said duct passing dow'n through the refrigerating compartment and leaving at the bottom to enter said load com- I partment near its bottom whereby primary air circulation may be induced by gravity in the duct.

ment and spaced from said heat transmitting wall so as to compel a gravity circulation of secondary cooling air in the refrigerating compartment and between the dry-ice lchest and said heat transmitting wall, the flow of said cooling air adjacent said wall being upward and counter to the flow of said primary circulation' within the duct,

. the gravity circulation-of secondary air being independent of-any circulation ofJprimary air, or of material in the chest and means for discharging gas from thedry-ice chest to the atmosphere.

V v Davm c. JESSE A. GUYER. 

